Switches are very popular components used in various industrial fields. Industrial process systems and devices often require switching among alternative modes or controllers to satisfy multiple optimal objectives. Such examples include switching from manual to automatic control states. Other examples include switching from one controller, such as a proportional controller, to another controller, such as a proportional-integrate controller for a process.
When switching between controllers or modes (switchover), the difference between the outputs of different controllers or modes produces a discontinuous bump in the process input. This, in turn, causes undesirable bumps in the controlled output variables. This difference or mismatch can deeply deteriorate the performance of the process. Such phenomenon is referred to as the bump transfer. The issue of avoiding process bump transfer is one of the most important issues in industry processes. A goal of switching is to realize a smooth transition of bumpless transfer between different controllers or process operating modes. Technology used to realize a smooth transition is referred to as bumpless transfer technology.
The purpose of bumpless transfer is to keep the control signal sent into the controlled plant continuous when the switching occurs. Most current bumpless transfer control devices in use today rely on the operating information of the system or specific system design technology. This method requires a designer to know the process mode or the controller states. Thus, it requires the controller states to always be computable. Therefore, it is a challenge for bumpless transfer devices to be applied in different processes and different areas of the industry. Another challenge for bumpless transfer devices is to be used easily by people who are not familiar with a special system or process.